Problem: A permutation p is an ordered group of numbers p1, p2, ..., pn, consisting of n distinct positive integers, each is no more than n. We'll define number n as the length of permutation p1, p2, ..., pn.

Simon has a positive integer n and a non-negative integer k, such that 2k ≤ n. Help him find permutation a of length 2n, such that it meets this equation: <image>.

Input

The first line contains two integers n and k (1 ≤ n ≤ 50000, 0 ≤ 2k ≤ n).

Output

Print 2n integers a1, a2, ..., a2n — the required permutation a. It is guaranteed that the solution exists. If there are multiple solutions, you can print any of them.

Examples

Input

1 0


Output

1 2

Input

2 1


Output

3 2 1 4


Input

4 0


Output

2 7 4 6 1 3 5 8

Note

Record |x| represents the absolute value of number x. 

In the first sample |1 - 2| - |1 - 2| = 0.

In the second sample |3 - 2| + |1 - 4| - |3 - 2 + 1 - 4| = 1 + 3 - 2 = 2.

In the third sample |2 - 7| + |4 - 6| + |1 - 3| + |5 - 8| - |2 - 7 + 4 - 6 + 1 - 3 + 5 - 8| = 12 - 12 = 0.

Solution (in JAVA):

Solution:
// Author @ BlackRise :) //
// Birla Institute of Technology, Mesra//
import java.io.*;
import java.util.*;

public class permutation {


    static void Blackrise() {                                                //The name Blackrise is my pen name... you can change the name according to your wish

        n = ni();

        tsc();

        int k=ni();

        for(int i=1;i<=2*n;i+=2)
        {
            if(k>0)p(i+1+" "+i);
            else p(i+" "+(i+1));
            k--;
        }
        flush();
        tec();                  //calculates the ending time of execution
        //pwt();                //prints the time taken to execute the program
    }


    /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////


    static Calendar ts, te;                                                  //For time calculation
    static int mod9 = 1000000007;
    static int n,t,MOD=998244353;
    static Lelo input = new Lelo(System.in);
    static PrintWriter pw = new PrintWriter(System.out, true);


    public static void main(String[] args) {                                 //threading has been used to increase the stack size.

        new Thread(null, null, "BlackRise", 1<<25)  //the last parameter is stack size which is desired,
        {
            public void run() {

                try {
                    Blackrise();
                } catch (Exception e) {
                    e.printStackTrace();
                    System.exit(1);
                }
            }
        }.start();
    }

    static class Lelo {                                              //Lelo class for fast input
        private InputStream ayega;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;

        public Lelo(InputStream ayega) {
            this.ayega = ayega;
        }

        public int read() {
            if (numChars == -1)
                throw new InputMismatchException();

            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = ayega.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }

                if (numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public String nextLine() {
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

        public int nextInt() {
            int c = read();

            while (isSpaceChar(c))
                c = read();

            int sgn = 1;

            if (c == '-') {
                sgn = -1;
                c = read();
            }

            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            }
            while (!isSpaceChar(c));

            return res * sgn;
        }

        public long nextLong() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;

            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            }
            while (!isSpaceChar(c));
            return res * sgn;
        }

        public double nextDouble() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            double res = 0;
            while (!isSpaceChar(c) && c != '.') {
                if (c == 'e' || c == 'E')
                    return res * Math.pow(10, nextInt());
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            }
            if (c == '.') {
                c = read();
                double m = 1;
                while (!isSpaceChar(c)) {
                    if (c == 'e' || c == 'E')
                        return res * Math.pow(10, nextInt());
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    m /= 10;
                    res += (c - '0') * m;
                    c = read();
                }
            }
            return res * sgn;
        }

        public String readString() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            }
            while (!isSpaceChar(c));

            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            return readString();
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
    }

    // functions to take input//
    static int ni() {
        return input.nextInt();
    }

    static long nl() {
        return input.nextLong();
    }

    static double nd() {
        return input.nextDouble();
    }

    static String ns() {
        return input.readString();
    }

    //functions to give output
    static void pl() {
        pw.println();
    }

    static void p(Object o) {
        pw.print(o + " ");
    }

    static void pws(Object o){
        pw.print(o+"");
    }

    static void pl(Object o) {
        pw.println(o);
    }

    static void tsc()                                          //calculates the starting time of execution
    {
        ts = Calendar.getInstance();
        ts.setTime(new Date());
    }

    static void tec()                                          //calculates the ending time of execution
    {
        te = Calendar.getInstance();
        te.setTime(new Date());
    }

    static void pwt()                                          //prints the time taken for execution
    {
        pw.printf("\nExecution time was :- %f s\n", (te.getTimeInMillis() - ts.getTimeInMillis()) / 1000.00);
    }
    static void flush()
    {
        pw.flush();
    }

    static void sort(int ar[])
    {
        for(int i=0;i<n;i++)
        {
            int ran=(int)(Math.random()*n);
            int temp=ar[i];
            ar[i]=ar[ran];
            ar[ran]=temp;
        }
        Arrays.sort(ar);
    }
    static void sort(long ar[])
    {
        for(int i=0;i<n;i++)
        {
            int ran=(int)(Math.random()*n);
            long temp=ar[i];
            ar[i]=ar[ran];
            ar[ran]=temp;
        }
        Arrays.sort(ar);
    }
    static void sort(char ar[])
    {
        for(int i=0;i<n;i++)
        {
            int ran=(int)(Math.random()*n);
            char temp=ar[i];
            ar[i]=ar[ran];
            ar[ran]=temp;
        }
        Arrays.sort(ar);
    }
}